spread4: Add POSIX link about -ldl

[Greg Troxel <gdt%lexort.com@localhost>]

Module Name:	pkgsrc-wip
Committed By:	Greg Troxel <gdt%lexort.com@localhost>
Pushed By:	gdt
Date:		Wed Sep 16 21:23:56 2020 -0400
Changeset:	94f663353fd70fbf7173dfee27fe3e66f82522e1

Modified Files:
	spread4/Makefile

Log Message:
spread4: Add POSIX link about -ldl

To see a diff of this commit:
https://wip.pkgsrc.org/cgi-bin/gitweb.cgi?p=pkgsrc-wip.git;a=commitdiff;h=94f663353fd70fbf7173dfee27fe3e66f82522e1

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.

diffstat:
 spread4/Makefile | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diffs:
diff --git a/spread4/Makefile b/spread4/Makefile
index 1de4927e14..debc02ff3d 100644
--- a/spread4/Makefile
+++ b/spread4/Makefile
@@ -56,8 +56,10 @@ post-install:
 	${INSTALL_DATA} ${WRKSRC}/docs/sample.spread.access_ip ${DESTDIR}${EXAMPLEDIR}/spread.access_ip
 
 .include "../../mk/dlopen.buildlink3.mk"
-# Work around upstream bug where -ldl is added on NetBSD.  Reported to
-# contact address on 20200830, with no response.
+# Work around upstream bug where -ldl is added on NetBSD.  Per POSIX,
+# the use of -ldl is irregular:
+#  https://pubs.opengroup.org/onlinepubs/9699919799/functions/dlopen.html
+# Reported to contact address on 20200830, with no response.
 BUILDLINK_TRANSFORM+=   opt:-ldl:${BUILDLINK_LDADD.dl:M*}
 
 .include "../../mk/pthread.buildlink3.mk"